Free, deregulated markets work well when the market participants have high information about what's in the market. If you're interested in buying, say, books, there's not much need to regulate what's in the books - customers have a pretty good idea, they can page through the book at the bookstore, and they can read what reviewers say.

Customers don't have any idea about which airline is safer. Airlines rarely have an idea of which airline is safer - shortcuts taken in manufacturing might lead to problems 20 years down the line when no human who was involved in the engineering or purchasing work is still at either company.